Extremophiles-&- Green House Effect: Life-in-Extreme- 2 Key Points Environments-- ! Energy has to get in Karen-Meech- ! It does not matter what wavelength ! Short wavelengths are most effective (most energy) With-input-from:--Bob-Bowers,-Doug-LaRowe-- ! The energy heats the surface of the planet (how much depends on albedo) - ! Infrared radiation (heat) has to be trapped ! Much or all of IR region of atmosphere has to be blocking light Review-of-Essentials-from- Early-Earth-&-Solar-System-Lectures- Life-Requirements-&-Origins- • UnDerstanDing-how-to-builD-a-habitable-worlD-&-how-it- evolveD- • We-Don’t-have-a-consensus-on-the-Definition-of-life- – Life-requires-water,-energy,-proDuces-waste,-replicates-anD-evolves- – When-DiD-Earth-form?--When-DiD-atmosphere-anD-oceans-form?- – Life-is-Carbon-baseD-(carbon-has-the-ability-to-make-complex-molecules)- – When-DiD-life-originate-on-Earth-(what-eviDence)?- – Life-occurs-in-a-microQenvironment-(cell)- – What-were-the-4-major-epochs-in-Earth-history-anD-how-are-they- • Steps-requireD-in-origin-of-life:--- characterizeD?- – creating-monomers-(organic-builDing-blocks),-creating-compartments,- creating-long-complex-molecules-(polymers),-creating-metabolic-networks-(E- • The$chemistry$of$the$atmosphere$can$regulate$planetary$temperature,$ proDuction)- and$environmental$conditions$on$the$surface$that$may$make$it$more$ • Quest-for-the-origin-of-life- or$less$habitable$to$life.$$There$is$a$lot$of$interaction$between$life,$ – Most-of-life-on-earth-through-time-has-been-microbial-"----------------------------------Does- atmosphere$and$geology,$and$we$don’t$fully$understand$all$the$ not-leave-many-fossils-(biomarkers)- feedback.$$Human$affects$cannot$be$fully$predicted.$ – Phylogenetic-trees-"-expressing-relateDness-of-life- • We$need$to$understand$what$life$requires$and$how$this$relates$to$a$ – 3-major-groupings-of-life:--Eukarya-(nucleateD-cells),--------------------------------------- habitable$environment$@$$and$what$are$considered$extremes.$ Archaea-(no-nucleus),-bacteria- Life-at-the-Extremes- Extreme-Habitats-&-Organisms- What-environmental-factors-are-important- for-classification-of-the-bounDaries-of-life?- • Life-has-occupieD-every-possible-niche-on-Earth- • Water-availability- – Two-key-habitability-markers:--water-anD-energy- • Temperature- – Explore-the-environments-anD-how-organisms-take-aDvantage-of-habitability- • Pressure- – This-gives-clues-to-other-habitable-solar-system-environments- • Salinity- • pH- • Extremophile- • Availability-of-energy- – Life-living-in-an-“extreme”-environment-(to-us)- • RaDiation-environment- - - • Classification-of-Microorganisms-relateD-to-habitats- Microbe(class( T(tolerences( • The-Energy-of-life- Psychrophiles- Q10-to-Q20oC- • Extreme-Environments-anD-their-resiDents-on-Earth- Mesophiles- 10-to-50oC- • Where-might-we-look-for-life-on-other-planets?- Thermophiles- 40-to-70oC- - Hyperthermophiles- >-80oC- - Arrows show T limits for plant and animal life Making a Living in the Microbial World • Metabolism-Definition- – The-chemical-processes-that-occur-within-a-living- organism-in-order-to-maintain-life- – Metabolism-makes-the-molecules-life-uses- • ReDox-Reactions- – Chemical-energy-is-storeD-in-highQenergy-electrons-that- are-transferreD-from-one-atom-to-another- – OxiDation-–-loss-of-electrons- – ReDuction-–-gain-of-electrons- ATP – molecule that life uses Shock&&&Holland&(2007)& for energy storage Making a Living in the Microbial World Metabolic Sources: • Autotrophs- Energy for Life – ProDuce-fooD- • What-Do-microbes-Do?--Catalyze-reactions- – – Anabolism-–-constructs-molecules-from-smaller-units-"-requires-E- Photoautotrophs:--photosynthesis-–-plants-convert-CO2,- • Synthesize-biomolecules,-polymerization,-maintain-membranes- H2O-anD-sunlight-to-sugar-(glucose)-anD-O2- – Catabolism-–-breaking-Down-molecules-to-release-energy- – Chemoautotrophs-–-make-energy-from-chemicals- – Metabolism-=-Catabolism-+-Anabolism- • Heterotrophs--- – FeeDers- Figure from D. LaRowe, UHNAI Winter school 2014 Microbial-metabolic-Diversity- Quantifying-the-Metabolic-process- • Constraints-on-Metabolism- – Nutrients- – Trace-metals- – Energy-available- – Environment:-T,-Pressure,-salinity- • Gibbs-Energy- – Amount-of-chemical-energy-available- e/(Donors( e/(Acceptors( Organics-- O2- H2- SO42Q- NH4Q- NO3Q- H2S- Fe(III)- Fe2+- CO2- CH4- Mn(IV)- Ogunseitan – Microbial Diversity Potential-Microbial-Metabolic-Processes- Conditions Electron Electron C source Metabolic process ThermoDynamics-–-Energy-limitations- (energy) donor acceptor Aerobic H2 O2 CO2 H2 oxidation - o 2- HS , S , S2O3 , O2 CO2 S oxidation 2- S4O6 + Fe2 O2 CO2 Fe oxidation + Mn2 O2 CO2 Mn oxidation + - NH4 , NO2 O2 CO2 Nitrification CH4 (& other C-1 O2 CH4, CO2, CO Methane (C-1) oxidation compounds Organics O2 Organics Heterotrophic metabolism Figures from D. LaRowe, UHNAI Winter school 2014 - Anaerobic H2 NO3 CO2 H2 oxidation o 2- H2 S , SO4 CO2 S & sulfate reduction • Amount-of-Energy-available-in-chemical-reactions- H2 CO2 CO2 Methanogenesis – DepenDs-on-temperature-anD-pressure- 2- CH4 SO4 ? Methane oxidation – How-this-changes-with-T-anD-P-is-Different-for-every-compounD- - Organics NO3 Organics Denitrification – A-negative-value-of-Gibbs-energy-inDicates-there-is-a-thermoDynamic- o 2- Organics S , SO4 Organics S & sulfate reduction Drive-for-the-reaction-to-proceeD-(useful-for-the-organism-to-get-energy)- Organics Organics Organics Fermentation Courtesy J. Cowen; NAI WS 2005 presentation Energetics-Examples- Microbial-life-exploits-energy- graDients-with-reDox-transitions- • From-Yellowstone-Hot-springs- – Each-line-is-a-possible-catabolic-reaction- – Each-depends-on-T-and-composition-of-hot- spring- • Example-ReDox-reactions- Methanogenesis CO2 + 4H2 " CH4 + 2H2O CH4 + 2O2 " CO2 + H2O Sulfur oxidation or reduction The-reDoxQcouples-are-shown-on-each-stairQstep,- S + 1.5O + H O " SO 2- + 2H+ 2 2 4 where-the-most-energy-is-gaineD-at-the-top-step-anD- S + H " H S 2 2 the-least-at-the-bottom-step.--- Figures from D. LaRowe, UHNAI Winter school 2014 Extremophiles-&-Limits- How-much-E-is-neeDeD?- • What-do-we-mean-by-limit?- – Does-it-move-or-grow-or-Do-anything?-- -Activity- • Energetics-of-Growth- – Maintains-a-constant-population?- -Steady-state- – E-to-capture-biomolecules-(DepenDs-on-environ)- – Dying-slowly-enough-to-be-observeD?- -Persistence- – Polymerization-into-bigger-molecules- • BounDaries-between-these-states-are-not-well-known- – Aerobic-conDitions:-18.4-kJ-(g-cells)Q1- – Anaerobic-conDitions:-1.4-kJ-(g-cells)Q1- (LaRowe and Amend, 2014) • Energetics-of-SteaDy-State- – Defense-against-chemical-stress- – Maintaining-cell-- – In-some-environments,-this-is-a-very-small-number!-(1.6-J-/-yr-/-cmQ3)- • Energetics-of-Persistence- – Not-well-unDerstooD-–-but-very-low- Power supply Power supply Power supply (energy per < demand = demand unit time) > demand Summary-of-Important-Points- Parting- Thoughts- • Classification-of-Microorganisms-relateD-to-habitats- • Temperature:--psychrophiles,-mesophiles,-thermophiles,-hyperthermophiles- • Environment:--barophiles,-xerophiles,-halophiles,-acidophiles,-alkalaiphiles- • The-Energy-of-life-–--ReDox- • Chemical-energy-is-storeD-in-highQenergy-electrons-that-are-transferreD-from-one-atom-to-another- • Organisims-get-energy-from-light-or-chemicals-anD-the-carbon-from-inorganic-(CO2)-or-organic- • How-much-energy-is-avail-(Gibbs-energy)-DepenDs-on-environment-(T,-P,-chemistry)- • The-mantra-for-searching-for-life- • Classification-of-organisms-by-sources-of-Energy-anD-carbon-(phototroph,-chemotroph…..)- – Follow-the-water-has-been-NASA’s-goal-–-is-the-the-right-mantra?- • Classification-of-organism-by-whether-it-makes-fooD-or-eats-fooD-proDuceD- – Follow-the-energy-(reDox)?- • Extreme-Environments-anD-their-resiDents-on-Earth-- • Examples:-hyDrothermal-vents,-Deep-earth,-polluteD-areas,-Deserts,-antarctic….- • What-does-it-mean-to-be-a-mesophile?- • Where-might-we-look-for-life-on-other-planets?- – Are-we-the-extreme-organisms?- • Habitability-markers:--water-anD-reDox-potential- A-Preview-of-Future- Psychrophiles- • ColD-lovers- Lectures- – Temps-0Q20oC- – Survive-freeze/thaw- • Ancient-Crater-lakes-on-Mars- – ReproDuce-2oC- – There-was-clearly-a-perioD-in-Mars-history-where- – Often-tolerant-of-salty-conDitions- substantial-water-was-present-on-surface- • Habitats- – How-long?--How-much?- – Soils- – How-long-is-neeDeD-for-life-Development?- – Deep-ocean-water- – Where-to-look-for-fossils-of-that-early-life?- – Sea-ice- • Many-icy-satellites-have-oceans- • Least-stuDieD-of--extremophiles- – Europa,-Callisto,-EncelaDus- CH4 worms, Sea of Cortez Ice Psychrobacter, Antarctic Mesophiles- Eukaryotic-Thermophiles- • Salmonella Habitats- E-Coli – MoDerate-Temperatures- • 30Q60oC- – AciDic-environments-- • pH-1Q4- Sofolubus acidocauldarius (Italy) • All-are-anaerobes- • MoDerate-temperatures-–-most-common- – Solubility-of-O2-in-water- – Soil-bacteria- above-85oC-is-very-low- – Pathogens- • Most-pathogens-grow-best-at-37oC- Pyrodictium occultum – grows 105-115oC at – Most-food-spoilage-due-to-mesophiles- hydrothermal vents. Most primitive Thermus aquaticus Hyperthermophiles- Barophiles-–-Deep-Dwellers- • Prokaryotes- – Temperatures- • The-Geothermal-graDient- • o o Synechococcus Low:-45Q90 C- – T-increases-with-Depth-(~-1o C-per-km-below- • o (Yellowstone) Optimal-45Q80 C- 100-km)- • High-extreme-125oC- – pH:-1Q7.5- • Deep,-Dark-Dwelling-bacteria- – Can-survive-high-pressure- – Tolerate-high-T,-P-(>-100-atm)- • DiscovereD-within-last-30-yr- – Are-usually-thermophilic-